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To ALL WHoM rr MAY coNcEnN:

Be it *known that I, Oris Tur-rs, of Boston, in the county of Suffolk,and State of-Massachusctts, have invented an Improvement in Elevators;and 1 do hereby declare that the following, taken in connection with thedrawings which accompany and form part of this specification, isisdescriptionpf my invention suilicient to enable'those skilled in the artto practise it.

This invention relates to improvements upon my invention patented May28th, 1861, in such elevators as make use of a car guided between waysand suspended from its upper end by two or moreropes or chains, whichhave the ends of each separately attachedt the top oi' the car and tothewinding drum; And my herein described invention consists in s. peculiarsrrangementcf pivoted links herein described, operating automatically toequalize the strain upon a series of ropes or chains, attached eacl'v byone end, separately thereunto, primarily' and secondnrily thereby to thetop of a guided and suspended elevator car, and each by the otherv endto a winding drum. i

i The object of my invention is the same as that of thestrain-equalizing device described in my aforesaid patent, but theconstruction of the within described device being different, and todaconsiderable extent better and cheaper for some purpose; itishgreinelaimed as an improvement,"

Figure 1 of the drawings shows in front view an elevator embodying myinvention. Figure 2 is a vertical central section taken in the plane ofthe line z z, iig. 1.

Figure 3 is an elevation of my improvedautomatic adjuster of the strainon the tensile supports, the scale' being larger than that shown in g.1; and

Figure 4 is n.l detail introduced merely to show how the-automaticstrain adjusterV may be located. at the l drum, instead of at the top ofthe csr, though I would remark that such a changeis not accompanied withany beneficial results.

The 1st and 2d figs. of the drawing show plainly the general arrangementof an elevator, in which the car is guided by ways, and is suspendedfrom its upper end by a series of ropes or chains-which pass over aguiding pulley to a winding drum, all of which forming no part of mypresent invention, will not bc .more particularly referred to herein.

Pivoted to a suitable casting, r1, which is securely fixed at the top ofthe car, is a series of double or oppositeliuks, exceeding in the numberof pairs thereof the` number of suspending ropes' or chains, b lz b byone.

i Of these links the extremes, `c c, of the series are longer than theintermediates, d d d, which have but two pivot centres, e and f, whilethe extremes have three pivot centres, e, f, and g.- Each of the centresffff f, are

' connected with each of thc adjoining centrcsf, by pairs of links, h hh, said links also taking hold of crossconuecting bars, 'i i z', onwhich the links h pivot, each of said bars serving for a point ofattachment of one end ofAone of the ropes b. The tops of the links c care united by a pair of connecting links, j, pivoted at y g, and actingas a strut or brace to keep the extreme centres f from approaching eachother under the strain upon the ropes or chains b b b b. The arrangementof all of these links `in pairs enables mc to connect the ropes b b bl?, centrally between them to the bars z'z'i, and the pair of links j,are so united by studs lc, that they act together as one link with theropes passing between its twopsrts.

The opera-tion of this apparatus is as follows: lf all the rcpes'are ofan exact'length from the points where, as tangents, they touch theperiphery of the winding arm, to the points of their` attachment to thebars t' z', and if there is the same strain on each rope or-chain, thenthe angles formed by the links h will all be equal to each other, andthe links c d d d c will be vertical. Suppose, now,.one of the ropes toshrink or to shorten from any cause, it is evident that it will eithersustain the whole wcight'of the car and itscontents, leaving the otherropes slack, or else that the links h will so move as to bring an equalstress on all of the ropes'. Thclatter will he the case, as it is clearthat the links It', embracing that piece which receives thc shortenedrope, will forni-a more acuto angle by rising, which act causes theother links lto descend and form more obtusc'anglcs, while the links dwill swerve from their vertical position toward the shortened rope, andthe strain on all the ropes will he thus automatically adjusted to sueqnal strain on each. If one of the ropes stretches, then the linkswhich are connected to those pieces to which the other ropes areattached, rise, While the links attached to the piece which receives thelengthened ropefttll, the links d inclining from the lcngthened rope,and the strain,

the position of its parts,

s automaticallyl adjusted on all the ropes provided, as also in theprevious instance, that the change in the condition of the ropes is nottoo great for thc range of action of the adjusting mechanism, When oneormore of the ropes break, then the car falls till the links L, attachedto the piece or pieces 2', receiving the broken rope or ropes, assume ahorizontal position, the other links L forming smaller angles thanbefore such breakage, and

the stress will then be automatically transferred equally to the ropesremaining whole. The object of pivoting the links c at the bottom, asthe links d are pivotcd, is to allow the whole system oi links to swayfrom right to left, or vice versa, according as thc tendency of thedraught of the ropes inclnes the syste-m to move with reference to thecentre of gravity of the suspended car. Except for the advantagesderived from the swinging movement of the entire systemy of links, thecxtreme links 7L might be pivotcd to immovable supports, andl yet thesystem so modified would operate as described in respect toautomatically equalizingth'c strain onthe ropes or chains. As the rangeof motion of the parts of the described apparatus is but comparativelysmall, and as it s necessary for its operation that the length of theropes should be such as to causo the links to assume about a mediumposition between thoseV extremes of' movement which, under thecontemplated contingencies inproctical operation, they may be caused tomake, so that under changes of the conditions of theropcs or chains anyof their points of attachment, z'z'z'z', may be free to move up or down,it is extremely desirable to combine with an automatic adjuster of thestrain 'upon the tensile supports, some convenient means `ior soadjusting, by manipulation, the length of such supports, as that therebythe automatic adjuster may itself be adjusted as to to bring them to amean of the extremes of their limit of motion. This I accomplishasfollows: Each rope or chain b forming one of the tensile supportsof-the guided and suspended car, is attached to the winding drum m, asfollows: Tubular screws, Z, are made, through which the ropes or chainscan pass, and to which they are secured by enlargements thereof, whichcannot pass through the bore of' the screws, which by turning, A,can beadjusted in the drum relative to its periphery, thus lengthening orshortening the effective winding length of thc tensile supports, so thatthe centres of the pieces z' z' z' z' may all be brought to the sameline, from which they depart on account ofvarious reasons, in the actualuse of the elevator, causing the said centres to assume positions not inthe saine line or plane, as illustrated by red lines in Eg. 3.

I claim, forthc purpose of automatically' adjusting the strain upon theropes or chains 6 b, the mechanism herein described, when arranged tooperate substantially as specified. V v OTIS TUFTS. lVitnesses:

J. B. Ciaosnr, W. B. GLEAsoN.

